Instruction manual

SECTION 2. STATION INSTALLATION
2-5
The sensors are installed in the undisturbed
face of the hole. Measure the sensor depths
from the top of the hole. Make a horizontal cut,
with a knife, into the undisturbed face of the
hole and insert the heat flux plates into the
horizontal cut. Press the stainless steel tubes
of the TCAVs above the heat flux plates as
shown in Figure 2.5-1. Be sure to insert the
tube horizontally. When removing the
thermocouples, grip the tubing, not the
thermocouple wire.
Install the CS615 as shown in Figure 2.5-1.
See the CS615 manual (Section 5) for detailed
installation instructions.
Never run the leads directly to the surface.
Rather, bury the sensor leads a short distance
back from the hole to minimize thermal
conduction on the lead wires. Replace the
excavated soil back to its original position.
Finally, wrap the end of the thermocouple wire
around the 21X base at least twice before wiring
them into the terminal strip. This will minimize
thermal conduction into the terminal strip. After
all the connections are made, replace the
terminal strip cover.
2.6 WIRING
The CA27 and KH20 are shipped with 25 ft
standard lead lengths. Table 2.6-1 lists the
connections for the CA27 and the KH20.
FIGURE 2.5-2. TCAV Spatial Averaging Thermocouple Probe